block: Add status callback to bdrv_amend_options()

Depending on the changed options and the image format,
bdrv_amend_options() may take a significant amount of time. In these
cases, a way to be informed about the operation's status is desirable.

Since the operation is rather complex and may fundamentally change the
image, implementing it as AIO or a coroutine does not seem feasible. On
the other hand, implementing it as a block job would be significantly
more difficult than a simple callback and would not add benefits other
than progress report to the amending operation, because it should not
actually be run as a block job at all.

A callback may not be very pretty, but it's very easy to implement and
perfectly fits its purpose here.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414404776-4919-2-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Max Reitz 2014-10-27 11:12:50 +01:00 committed by Stefan Hajnoczi
parent 9ea92c2106
commit 7748543420
5 changed files with 15 additions and 6 deletions

View file

@ -268,7 +268,13 @@ typedef enum {
int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts);
/* The units of offset and total_work_size may be chosen arbitrarily by the
* block driver; total_work_size may change during the course of the amendment
* operation */
typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
int64_t total_work_size);
int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
BlockDriverAmendStatusCB *status_cb);
/* external snapshots */
bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,

View file

@ -232,7 +232,8 @@ struct BlockDriver {
int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result,
BdrvCheckMode fix);
int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts);
int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts,
BlockDriverAmendStatusCB *status_cb);
void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);